Noncorrosive antifreeze liquid



Patented Feb. 14, I939 NONCORRO SIVE AN TIFREEZE LIQUID Leo J. Clapsadle, Buffalo, and Alvan-H. Tenney,

Mount Vernon, N. Y., assignors, by mesne assignments, to Union Carbide and Carbon Corporation, a corporation of New York No Drawing. Application November 9-, 1935, Se-

rial No. 48,997. Renewed October 18, 1937 13 Claims. (Cl. 252-5) The invention relates to new liquid composltain alcohols, and in ethyl alcohol it is practitionsfor use in fluid cooling systems, shock abcally insoluble. With the latter alcohol, and sorbers, hydraulic lifts, and the like. It has others of low solvent power toward this constitparticular reference to new and useful inhibitors uent, it is, therefore, desirable to mix small for the prevention of metal corrosion in fluid amounts of methanol or a glycol such as ethyl- 5 systems employing an alcohol as an anti-freeze ene glycol, diethylene glycol, or propylene glymedium. col, any of which will form an alcohol mixture Alcohols of common usage as a freezing point capable of dissolving sufilcient sodium chromate depressant include methanol, ethanol, propanol, to insure its proper function in the inhibitor mixl or other mono-hydroxy alcohols, and the polyture. l

hydroxy alcohols, such as ethylene glycol, pro- A specific anti-freeze composition, representpylene glycol, diethylene glycol, and glycerine. ative of the invention will consist, for example, The invention is applicable to compositions conof an alcohol mixture of about 95 parts of ethyl taining any of these liquids, and where an alalcohol, and parts of a glycol, to which has been i cohol is referred to in the specification and added, in percentage by weight, 0.25% of sodium 15 claims, it is intended to include all of the satnitrite, 0.05% of sodium chromate (decahydrate), urated aliphatic hydroxy compounds or mixand 0.04% of sodium hydroxide. In this same tures thereof. It is an object of the invention composition, 0.14% by weight of triethanolto provide an alcohol heat-transfer or fluid presamine may be substituted for the sodium hyb sure medium, containing small additions of an droxide, and is equa y effective in its aCtiOIlinhibitor composition, adapted to protect iron, This three-component inhibitor provides procopper, brass, solder, aluminum, and other tection not only for iron, but for all other metals metals, from corrosive action commonly induced commonly s d in fluid Cooling and Pressure in normal uses of such liquids. A further obsystems. It inhibits corrosion to an extent quite ject is to effectively produce and maintain subimpossible with any one O the materials o stantially non-corrosive conditions in a cooling or any binary combination of them. Discolorafluid where an alcohol may be employed in full tion of aluminum, a condition difiicult to avoid strength, in mixture with other alcohols, or in with prior known inhibitors, is also prevented a diluted solution with water. by this mixture, under all normal operating con- We have found that a ternary mixture of n ditions. A clear solution is obtained, and the alkali metal nitrite, an a1ka1i met chromate, inhibitor remains soluble in the alcohol, in its and an alkaline component of an organic or inse a an ant eeze medium, both in full organic base, each in very small concentrations, strength and in diluted form. A protective film will accomplish this objective, and provide corpp s t form OR ron in Contact with the rosion protection for all metals commonly eminhibited 81001101, and this fi Will p v nt atployed in cooling and pressure systems. The inmospheric corrosion of surfaces in a cooling syshibitor is universally applicable in function with 158m Which during p t o me 6X- all of the known al ohol type anti-freeze liqposed. The inhibitor functions substantially as ujds well on surfaces contaminated with rust as it Sodium compounds are especially appropriate C1085 on the clean metal, and no foaming is enfor all three constituents, specifically sodium nicountered in alcohols containing trite, sodium chromate, preferably in the 1 It Will be understood that the invention is ahydrate form, nd di m hydroxide, T iapplicable in use with all of the common anti ethanolamine, or other hydroxy alkylamine, may freeze alcohols, where they mav be employed be substituted for the sodium hydroxide, as the both individually a in mixtures of two or free alkaline component of the mixture. Only more- In an automobile cooling syst m, the very small additions of each material are neces- 31001101 is usually diluted With Water, d in a y sary to provide a proper inhibiting action. While degree of aqueous dilution the inhibitor is equally the most effective concentration may vary with effective. Other dlluents, such'as kerosene, and

, different alcohols, a suitable range, by weight of very Small quantities of a y both f- Which the alcohol, is from 0.05% to 2.0% of sodium are sometimes used in anti-freeze solutions, will nitrite, 0.02% to 1.0% of sodium chromate, not affect the inhibiting action. Modification in 0.01% to 0.10% of sodium hydroxide, or in place the specific proportions given will be evident, and of the latter, 0.05% to 1.0% of triethanolamine. the most suitable inhibitor concentration for any Sodium chromate has a limited solubility in cerparticular alcohol base may be readily determined. While sodium compounds are preferred, similar salts of potassium or other materials, within the class indicated, may be equally effective.

The invention should not be limited other than as defined in the appended claims.

We claim:

1. A non-corrosive anti-freeze liquid comprising an alcohol and an inhibitor consisting of a mixture of an alkali metal nitrite, an alkali metal chromate, and an alkaline component 01 the group consisting of an alkali metal hydroxideand a hydroxy alkylamine.

2. A non-corrosive anti-freeze liquid comprising an alcohol and an inhibitor consisting of a mixture of an alkali metal nitrite, an alkali metal chromate, and a member of the group consisting of sodium hydroxide and triethanolamine.

3. A non-corrosive anti-freeze liquid compris ing an alcohol and an inhibitor consisting of a mixture of about 0.05% to about 2.0% of an alkali metal nitrite, about 0.02% to about 1.0% of "an alkali metal chromate, and about 0.01% to about 0.10% of an alkali metal hydroxide.

4. A non-corrosive anti-freeze liquid comprising an alcohol and an inhibitor consisting of a mixture of about 0.05% to about 2.0% of an alkali metal nitrite, about 0.02% to about 1.0% of an alkali metal chromate, and about 0.5% to 1.0% of a hydroxy alkylamine.

5. A non-corrosive anti-freeze liquid comprising an alcohol and an inhibitor consisting of a mixture of about 0.05% to about 2.0% of sodium nitrite, about 0.02% toabout 1.0% of sodium chromate, and about 0.01% to 0.10% of sodium hydroxide.

6. A non-corrosive anti-freeze liquid comprising an alcohol and an inhibitor consisting of a mixture of about 0.05% to about 2.0% of sodium nitrite, about 0.02% to about 1.0% of sodium chromate, and 0.05% to about 1.0% of triethanolamine.

7. A non-corrosive anti-freeze liquid comprising an alcohol mixture of about 95 parts ethyl alcohol and 5 parts of a glycol, and-an inhibitor consisting of a mixture of about 0.25% sodium nitrite, about 0.05% sodium chromate, and about 0.04% sodium hydroxide.

8. A non-corrosive anti-freeze liquid comprising an alcohol mixture of about 95 parts ethyl alcohol and 5 parts of a glycol, and an inhibitor consisting of a mixture 01 about 0.25% sodium nitrite, about 0.05% sodium chromate, and about 0.14% triethanolamine.

9. Method of inhibiting corrosion of metals by an alcohol solution in contact therewith, which comprises contacting said solution with metals in the presence oi. an inhibitor mixture consisting of an alkali metal nitrite, an alkali metal chromate, and an alkaline component oi the group consisting of an alkali metal hydroxide and a hydroxy alkylamine.

10. A method of inhibiting corrosion of metals by an alcohol in contact therewith, which comprises contacting said alcohol with metals in the presence of an inhibitor mixture consisting of sodium nitrite, sodium chromate, and a member of the group consisting of sodium hydroxide and triethanolamine.

11. Method of inhibiting corrosion of metals by an alcohol-solution in contact therewith, which comprises contacting said alcohol with metals in the presence of about 0.05% to about 2.0% sodium nitrite, about 0.02% to 1.0% sodium chromate, and about 0.01% to 0.10% sodium hydroxide.

12. Method of inhibiting corrosion of metals by an alcohol solution in contact therewith, which comprises contacting said alcohol with metals in the presence of about 0.05% to about 2.0% sodium nitrite, about 0.02% to 1.0% sodium chromate, and 0.05% to about 1.0% of triethanolamine.

13. A non-corrosive anti-freeze liquid comprising an alcohol and an inhibitor consisting of a soluble nitrite salt, an alkali metal chromate, and an alkaline component of the group consisting of an alkali metal hydroxide and a hydroxy alkylamine. LEO J. CLAPSADLE. ALVAN H. 'I'ENNEY. 

